From 00498e48c967c236fde52a1a17ee05958501b755 Mon Sep 17 00:00:00 2001
From: Jasper Boeijenga <jboeijenga@gmail.com>
Date: Thu, 20 Mar 2025 15:52:32 +0100
Subject: [PATCH 1/2] Added more feedback in case branch is already created

Signed-off-by: Jasper Boeijenga <jboeijenga@gmail.com>
---
 .../src/actions/gitlabMergeRequest.ts         | 44 ++++++++++++++-----
 1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/plugins/scaffolder-backend-module-gitlab/src/actions/gitlabMergeRequest.ts b/plugins/scaffolder-backend-module-gitlab/src/actions/gitlabMergeRequest.ts
index 89ae1bddf2..49b7b501d4 100644
--- a/plugins/scaffolder-backend-module-gitlab/src/actions/gitlabMergeRequest.ts
+++ b/plugins/scaffolder-backend-module-gitlab/src/actions/gitlabMergeRequest.ts
@@ -414,20 +414,39 @@ which uses additional API calls in order to detect whether to 'create', 'update'
               execute_filemode: file.executable,
             }));
 
-      let createBranch: boolean;
-      if (actions.length) {
-        createBranch = true;
-      } else {
-        try {
-          await api.Branches.show(repoID, branchName);
-          createBranch = false;
-          ctx.logger.info(
-            `Using existing branch ${branchName} without modification.`,
-          );
-        } catch (e) {
-          createBranch = true;
+      let createBranch = actions.length > 0;
+
+      try {
+        const branch = await api.Branches.show(repoID, branchName);
+        if (createBranch) {
+          const mergeRequests = await api.MergeRequests.all({
+            projectId: repoID,
+            source_branch: branchName,
+          });
+
+          if (mergeRequests.length > 0) {
+            // If an open MR exists, include the MR link in the error message
+            throw new InputError(
+              `The branch creation failed because the branch already exists at: ${branch.web_url}. Additionally, there is a Merge Request for this branch: ${mergeRequests[0].web_url}`,
+            );
+          } else {
+            // If no open MR, just notify about the existing branch
+            throw new InputError(
+              `The branch creation failed because the branch already exists at: ${branch.web_url}.`,
+            );
+          }
         }
+
+        ctx.logger.info(
+          `Using existing branch ${branchName} without modification.`,
+        );
+      } catch (e) {
+        if (e instanceof InputError) {
+          throw e;
+        }
+        createBranch = true;
       }
+
       if (createBranch) {
         try {
           await api.Branches.create(repoID, branchName, String(targetBranch));
@@ -439,6 +458,7 @@ which uses additional API calls in order to detect whether to 'create', 'update'
           );
         }
       }
+
       await ctx.checkpoint({
         key: `commit.to.${repoID}.${branchName}`,
         fn: async () => {

From d86ce219a6602197ca99d944778815f685eb75e8 Mon Sep 17 00:00:00 2001
From: Jasper Boeijenga <jboeijenga@gmail.com>
Date: Thu, 20 Mar 2025 15:55:16 +0100
Subject: [PATCH 2/2] Added changeset

Signed-off-by: Jasper Boeijenga <jboeijenga@gmail.com>
---
 .changeset/gold-bugs-rhyme.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/gold-bugs-rhyme.md

diff --git a/.changeset/gold-bugs-rhyme.md b/.changeset/gold-bugs-rhyme.md
new file mode 100644
index 0000000000..e636e3f62f
--- /dev/null
+++ b/.changeset/gold-bugs-rhyme.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-scaffolder-backend-module-gitlab': minor
+---
+
+Added additional feedback in case branch is already created